This invention relates to a method of operating a data processing system, and in particular to a method of providing copies of data stored in storage devices to guard against the possibility of the storage devices becoming faulty or the data becoming corrupted, lost or, more recently, "infected by a computer virus". The invention is especially concerned with the provision of backups for personal computers (P.C.s).
With the increasing capacity of fixed storage media such as hard disk drives (now typically having storage capacities of upwards of 40 megabytes), the time and effort involved in making security copies of a disk is increasing.
At present, there are two options available to the average P.C. user. Commercial software exists to speed up the process of copying data onto a series of floppy disks. Whilst being an inexpensive solution, the method is tedious and time consuming. A 40 megabyte hard disk would at best require over 30 floppy disks to be fully copied, with the user required to change the disks throughout the backup.
The most effective option, however, is to copy the data on to a removable tape cartridge. Typically only one cartridge would be necessary, and for a 40 megabyte drive, the process would typically be completed in around fifteen minutes.
These methods have two drawbacks in addition to those already mentioned. Firstly, in each case, the user must make a conscious decision to perform the backup. The P.C. must be instructed to run the backup program, and the user must then wait for completion before a copy is available. Secondly, no existing backup method gives total protection against loss of data since the copied data exists only as an image of the storage medium at the time the copy was made, and subsequently stored data cannot be protected. It is an object of this invention to provide a means of backing up stored data which offers the possibility of overcoming such disadvantages.